From: Olof Johansson <olof@lixom.net>
To: Prathyush K <prathyush@chromium.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
Prathyush K <prathyush.k@samsung.com>,
linux-arm-kernel@lists.infradead.org,
linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org
Subject: Re: [PATCH] arm: dma mapping: export arm iommu functions
Date: Fri, 28 Dec 2012 22:53:56 -0800 [thread overview]
Message-ID: <20121229065356.GA13760@quad.lixom.net> (raw)
In-Reply-To: <CAH=HWYP5r18qjQSc_2121vikbTMpYv6DKOfW=hpOpGB7rUyNRA@mail.gmail.com>
On Fri, Dec 28, 2012 at 09:53:47AM +0530, Prathyush K wrote:
> On Thu, Dec 27, 2012 at 7:45 PM, Marek Szyprowski
> <m.szyprowski@samsung.com>wrote:
>
> > Hello,
> >
> >
> > On 12/27/2012 8:14 AM, Prathyush K wrote:
> >
> >> This patch adds EXPORT_SYMBOL calls to the three arm iommu
> >> functions - arm_iommu_create_mapping, arm_iommu_free_mapping
> >> and arm_iommu_attach_device. These functions can now be called
> >> from dynamic modules.
> >>
> >
> > Could You describe a bit more why those functions might be needed by
> > dynamic modules?
> >
> > Hi Marek,
>
> We are adding iommu support to exynos gsc and s5p-mfc.
> And these two drivers need to be built as modules to improve boot time.
>
> We're calling these three functions from inside these drivers:
> e.g.
> mapping = arm_iommu_create_mapping(&platform_bus_type, 0x20000000, SZ_256M,
> 4);
> arm_iommu_attach_device(mdev, mapping);
The driver shouldn't have to call these low-level functions directly,
something's wrong if you need that.
How is the DMA address management different here from other system/io mmus? is
that 256M window a hardware restriction?
-Olof
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next prev parent reply other threads:[~2012-12-29 6:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-27 7:14 Prathyush K
2012-12-27 14:15 ` Marek Szyprowski
2012-12-28 4:23 ` Prathyush K
2012-12-29 6:53 ` Olof Johansson [this message]
2013-01-01 1:07 ` Subash Patel
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